Modern medical and wellness practices increasingly make use of self-administered tests and self-collection of test specimens. For instance, U.S. Pat. Nos. 5,978,466; 6,014,438; 6,016,345; and 6,226,378, issued to Richard Quattrocchi and assigned to Home Access Health Corporation of Hoffman Estates, Ill., all disclose a method of anonymously testing for a human malady. In accordance with certain embodiments of the subject matter disclosed in the foregoing patents, a patient obtains a blood specimen, typically by pricking his or her finger, and allows the blood to wick onto a blood spot card. After the card has dried, the user then sends the blood spot card to a medical testing facility, where it is tested to determine whether the patient is afflicted with a specific malady. The user may contact the facility anonymously to receive the test result.
The subject matter of the foregoing patents is usable in connection with testing for the presence of human antibodies directed against viral antigens in the blood, for instance, in determining whether a patient is infected with HIV (human immuno-deficiency virus) or with a hepatitis virus. Another document, U.S. Pat. No. 5,435,970, issued to Mamenta et al. and assigned to Environmental Diagnostics, Inc. of Burlington, N.C., discloses a device for separating blood cells from biological fluids, for instance, for separating serum from whole blood. The device disclosed in the '970 patent purports to enable the shipment and testing of a serum sample.
The blood spot and serum specimen cards known in the art are suitable for use in the collection of specimens for qualitative testing, i.e., testing for the presence or absence of a given compound in blood or a given medical condition. Heretofore, however, such blood spot and serum cards have been somewhat unsatisfactory in the quantitative testing of blood and serum specimens.
For instance, general wellness protocol indicates the measurements of a patient's total cholesterol value, which is the number of milligrams of total cholesterol in a deciliter of blood. The value is often used in conjunction with a full lipid profile, which provides levels of triglycerides, HDL (high density lipoprotein) cholesterol, and LDL (low density lipoprotein) cholesterol in a patient's blood. It can be very difficult to gauge the amount of blood or serum that is present in the blood or serum spot card. Particularly when the blood or serum spot card has been self-prepared by a person without medical training, it is difficult to know to certainty whether the spot card has been “underfilled” with less than the intended quantity of blood or serum or “overfilled” with more than the intended quantity. If the amount of blood and serum varies by even a small amount over or under the expected level, the usefulness of the quantitative test can be severely diminished. For instance, it is generally thought that a person's total cholesterol number should be under 200 mg/dl, with cholesterol numbers above 240 mg/dl being considered high and with intermediate cholesterol number being deemed borderline. A 10% margin of error in a cholesterol determination of 220 mg/dl provides no information as to whether the person's cholesterol level is low, intermediate, or high.
In recognition of these problems, the prior art has provided attempts to provide a quantitative determination of analyte levels in a blood specimen. For instance, U.S. Pat. No. 6,040,135, issued to Steven Tyrell and assigned to Biosafe Laboratories, Inc., Chicago, Ill., purports to disclose a method for correcting for blood volume in a serum analyte determination. The method that is purportedly disclosed by this document is limited and is believed generally to be somewhat unsatisfactory.
The invention seeks to improve upon prior art testing methods, and to provide a method for quantitative testing of modified specimens such as dried blood spot and dried serum specimens.